World of Warcraft Launch: November 23, 2004
Hurricane Katrina Formed: August 23, 2005

Notice how, Blizzard, while still a successful company at the time, were nowhere near where they are today. Also notice that the Pet store or anything like it (Money for in-game items) was nowhere near "out" at the time of the Hurricane.

More importantly, note that Blizzard is a company, not a charity, and while it is very generous of them to do things like this, it is in no way their obligation.

Also keeping this time line in mind, the blizzard store wasn't even around until Wrath of the Lich King. Which was what, the end of 2008 when it was launched so I'm pretty sure the pet store didn't launch until 2009.

This is probably why blizzard was so reluctant to donate any money from the pets anyway because of people like you, the OP, who aren't satisfied with anything a company does try to do for the better good.

Considering that the Store didn't even exist at the time, and the rest of the thread is people ragging on the OP, I'm going to go ahead and close this, since I see no further benefit of leaving it open for discussion.